Scale



April 22, 1952 c. s. scHRoEDER SCALE 2 SHEETS-SHEET l Filed July :50, 1947 Patented Apr. 22, 1952 SCALE Charles S. Schroeder, Philadelphia, Pa., assignor to The Yale & Towne Manufacturing Company, Stamford, Conn., a corporation of Connecticut Application July 30, 1947, Serial No. 764,641

7 Claims. l

This invention rela-tes to a weighing scale, and more particularly, to means for limiting the movement between a knife edge pivot member and a beam bearing of the usual well known Weighing scale.

Those skilled in the art know that in Weighing scales it is necessary to employ knife edge pivot members on which beams, levers or the like are supported for pivotal movement through bearings that rest against the knife edges of the said pivot members. In this way, the beams, levers, or the like may transmit a load to a lever or other part carrying the knife edge pivot member, while allowing some movement of the parts relatively to one another.

In assemblies of the particular cla-ss, it is desirable to limit the longitudinal movement of the beam and its bearing relatively to the knife edge member. This longitudinal movement, when it takes place, comprises a. sliding' movement of the beam and its bearing on the knife edge of the knife edge pivot member. Naturally, it is necessary that this limiting action take place without the development of friction, since friction will interfere greatly with the proper action of the scale. It is the object of my invention to contribute limit means of the class described that will operate with a minimum of friction.

As a feature of my invention, I utilize a knife edge pivot member whose ends flare outwardly from the base thereof toward the knife edge thereof, so as to form a peak at each end of the {nife edge pivot member. Those skilled in the art will appreciate that in some assemblies only one end of the knife edge pivot member need be so formed.

As a further feature of invention, I utilize a limit member having a surface. or surfaces adapted to eoact with the said peak or peaks, the eoaction being such that a minimum ci friction must naturally develop, since the contact between the limit member and the peak is a point contact.

While it is the main feature of my invention to utilize the particular combination of a knife edge pivot member and limit member set forth, those skilled in the art will appreciate that it is possible to use other cooperating arrangements of a limit member and a knife edge pivot member embodying the basic concept of my inven. tion; that is, the utilization of surfaces coacting with a minimum of friction. Therefore, this invention should not be limited merely to the utilization of the particular surfaces that. I believe yield the best results.

As a still further feature of my invention, the limit member is preferably in the form of a cap adapted to coact with the beam bearing and having anges overlying the ends of the knife edge pivot member. As a still further feature of this part of the invention, the limit member or cap, as I call it, is adapted for movement relatively to the beam bearing so as to adjust itself to a proper operating position.

I have thus outlined rather broadly the more important features of my invention in order that the detailed description thereof that follows may be. better understood, and in order that my contribution to the art may be better appreciated. There are, of course, additional features of my invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which my disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the` several purposes of my invention.

Referring now to the drawings, Fig. l is a section through a portion of a typical scale platform mounting assembly, Vshowing my invention in such an assembly. Fig 2 is a cross section of Fig. 1 taken along lines 2--2. Fig. 3 is an exploded view of the parts utilized in my invention. Fig. 4 is an enlarged view showing the point contactbetween the limit member and the knife edge pivot member, forming the basis of my invention.

Referring now more particularly to the drawings, reference numeral I0 indicates a part of the main frame surrounding the movable platform of the scale. Welded thereto and forming a portion thereof is a vertical structural member I I, and welded to this vertical structural member at I2 is what is termed a corner block i3. Corner block I3 is formed with a bore I4 in which is supported a corner bearing pan I5. The main lever of the scale is designated by reference numeral I6, and carries a knife edge pivot I'I resting on the corner bearing pan. A suitable limit bolt I8 carried by a bracket I9 on structural member II prevents upward movement of the main lever I6 and its knife edge pivot member I1 from the pan I5. Insofar as I have described my scale, it merely utilizes those features Well known and understood by those skilled in the art. 4

Welded to the main lever I6 is a main, lever knife` bracket 20 comprising a pair of spaced plates 2| best illustrated in Fig. 3 as suitably reinforcedl by an end plate 22. The plates 2 I are formed with holes 23 and with retainer slots 24. Secured within the retainer slots 24, and bridging the space between the plates 2l, is a knife edge pivot member 25. It is usual in the art to stake the knife edge pivot member 25 securely into position relatively to the plates 2l of the bracket E@ so that the knife edge pivot member will not move longitudinally on the said bracket 2e.

A beam bearing tformed with a bearing groove 2? is then placed on the knife edge 23 of the knife edge pivot member 25. Ccacting with the beam bearing 26 is what I term a load suspension link 29 having earsl 35i formed with bores 3i. These bores 3i are adapted for alignment with a bore 32 of the beam bearing 2b, and through the aligned bores Si, 32 there is inserted a pin 35i held against endwise movement relatively to the suspension link 2G and beam bearing 2S by cotter pins Sli. A cross par 35 lies lengthwise in the openings 23 of the plates 2l of bracket 20 and rests at its center on the'bearing surface 36 of the load suspension link 29, as is probably best seen "in Fig. l. The cross bar 35 is formed with square ends Si adapted for coaction with the square notches 3d of a suspension bracket 39, this suspension bracket Sek being adapted to support in turnwhat I term the top rame il of the scale.

It is now obvious that through the suspension bracket 39', the load placed on the top frame `4!) is applied'to the cross bar 35, and that through the bar S the lload is in turn applied to the load suspension link 2Q. It then follows that through the load suspension link EQ the load is appliedto the beam bearing 2t and then through the knife edge pivot member 25 to the main lever knife bracket 2d. Gf course, through this main lever knife bracket 2f! the load is then applied to the main lever i8.

For limiting endwise movement of the beam bearing 26 and its surface il relatively to the knife edge pivot member 25', Ilu'tilize what I term a link end thrust cap @il having ears 42 and end flanges The ears [i2 are pierced at lil for the pin 33 so that when the pin 33 secures the load suspension link to the beam bearing 26, it simultaneously securesthe link end thrust cap t! in position. 0f course, the cap il will be free to move pivotally relatively to the pin 33 so as to adjust itself into a proper operating position.

The ends of the knife edge pivot memberV V2 5 'are tapered outwardly towards the knife edge 278 as is best illustrated in Figs. l and 4. As a result, each end of the knife edge pivot member 25 will terminate in the form of a4 peak t5. Each of the said peaks gif-. is adapted for coaction with a fiange of the cap asis best shown in Fig. 4, this coaction being in the form of a point contact between the parts. Those skilled in the art will understand that through a point contact a mini'- mum cf friction is developed between a flange 43 of `cap il and one of the peaks 45 of the knife edge pivot member 25.- the flanges Contact one Vof the peaks d5, the parts will ccact to limit any further movement in a particular direction between'thev beam bearing 2G andthe Vknife edge pivot member 25. While effective limiting action will result, the friction between the parts will be at a minimum because of the point Contact between the fiarige 43 and thepeak g 'I believe that the simplicity Of'lmy invention and the ease lwith' which it is fabricated and utilized and assembled in a scale, will now be quite apparent to those skilled in the art. i

Therefore, should vone ofV 4 I now claim:

1. In a scale of the class described, a knife edge pivot member, a. nat undersurface on the base of said knife edge pivot member of greater longitudinal extent than the knife edge of said knife edge pivot member, a supporting member having a iiat upper surface upon which the flat undersurface of said knife edge pivot member rests, a beam having a bearing surface bearing against the knifeedge of said knife edge pivot member, a limit member carried on said beam for limiting endwise .relative sliding movement between said knife edge pivot member and beam and therebiI limiting lateral relative movement between said beam and said supporting member, said knife edge pivot member flaring endwardly outwardly from its base towards its knife edge to present a peak or point surface to a surf-ace of said limit member whereby to reduce toa minimum friction between said limit member and said knife edge pivot member upon contact therebetween.

2. In ascale of the class described, a knife edge pivotv member, a beam having a bearing surface bearing against the knife edge of said knife edge pivot member, a cap for said beam, a pivot shaft bearing on said beam in yan axis transverse of the knife edge of said knife edge pivot member and engaged with said cap for pivotally securing said cap to said beam, flanges formed on said cap adapted to overlie the opposed ends of said knife edge pivot member for limiting endwise relative sliding movement between said knife edge pivot member and beam, said knife edge pivot member flaring endwardly outwardly at each end from its base towards its knife edge to present a peak or point surface to each of the flanges of said cap whereby to reduce to a minimum friction between said cap and said knife edge pivot member upon contact therebetween.

3. In a scale of the class described, a knife edge pivot member, Ya beam having a bearing surface bearing against the knife edge of said knife edge pivot member, a bearing pin traversing a bore in said beam transverse of the axis of its bearing surface and said knife edge, a load suspension link having opposed legs supported by said pin whereby a load is applied to said beam, a cap for said beam, opposed ears formed on said cap and having bores for said bearing pin whereby said cap is secured to said beam while adapted for some movement of adjustment relatively thereto, iianges formed on said cap adapted to overlie the opposed ends of said knife edge pivot member for limiting endwise relative sliding movement between said knife edge pivot member and beam, said knife edge pivot member flaring endwardly outwardly at each end from its base towards its knife e'dge to present a peak or point surface to each of the flanges of said cap whereby to reduce to a minimum friction between said cap and said knife edge pivot member upon contact therebetween.

4. In :a scale of the class described, a knife edge pivot member, a -beam having a bearing surface bearing against the knife edge of said knife edge pivot member, a cap for said beam, a pivot shaft bearing on said beam in an axis transverse of the knife edge of said knife edge pivot member and engaged with said cap for pivotally securing said cap to said beam, flanges formed on said cap adapted to overlie the opposed ends of said knife edge pivot member for limiting endwise relative sliding movement between said knife edge and beam, said knife edge having its end surfaces coacting with said flanges so shaped relatively to the shaping of said flanges whereby to minimize friction inherent upon contact therebetween.

5. In a scale of the class described, a knife edge pivot member, a beam having a bearing surface bearing against the knife edge of said knife edge pivot member, a bearing pin traversing a bore in said beam transverse of the aXis of its bearing surface and said knife edge, a load suspension link having opposed legs supported by said pin whereby a load is applied to said beam, a cap for said beam, opposed ears formed on said cap and having bores for said bearing pin whereby said cap is secured to said beam while adapted for some movement of adjustment relatively thereto, flanges formed on said cap adapted to overlie the opposed ends of said knife edge pivot member for limiting endwise relative sliding movement between said knife edge pivot member and beam, said knife edge pivot member and said flanges tapering relatively to one another to minimize the surface contact therebetween whereby to minimize friction inherent upon contact therebetween.

6. In a scale of the class described, a knife edge pivot member, said knife edge pivot member flaring endwardly outwardly from points inwardly of each end of its base towards its knife edge to present a peak or point surface to a limit or other surface movable relatively thereto whereby to minimize friction between said knife edge pivot member and said limit or other surface.

7. In a scale of the class described, a knife edge pivot member, a beam having a bearingr surface bearing against the knife edge of said knife edge pivot member, a bearing pin traversing a bore in said beam transverse of the axis of its bearing surface and said knife edge, a load suspension link having opposed legs supported by said pin whereby a load is applied to said beam, a cap for said beam, opposed ears formed on said cap and having bores for said bearing pin whereby said cap is secured to said beam while adapted for some movement of adjustment relatively thereto, and flanges formed Aon said cap adapted to overlie ie opposed ends of said knife edge pivot member f or limiting endwise relative sliding movement between said knife edge pivot member and beam.

CHARLES S. SCHROEDER.

EEFERENGES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 606,529 Finn June 28, 1898 1,100,258 Richmond June 16, 1914 1,143,647 Riedel June 22, 1915 1,472,037 Bagg Oct. 30, 1923 1,706,977 Hurt Mar. 26, 1929 

